Embodiments of the present invention relate to control of wafers throughout various semiconductor manufacturing processes.
Semiconductor devices are formed by performing many different manufacturing steps on wafers that are processed together in a group commonly referred to as a lot. Lots travel throughout various process tools of a semiconductor manufacturing facility to enable the different processes to be performed. Typically, there is significant human involvement in moving the lots between tools and selecting appropriate tools on which to process the lots. As a result, labor costs are high, and throughput times to obtain completed semiconductor wafers are high.
Accordingly, automated handling systems have been introduced to allow lots to travel between different process tools via an automated system. Furthermore, systems exist to automatically schedule lots to given tools. Many tools and processes still, however, are controlled manually. Current systems cannot readily accept manual input, such as needed to perform special processing on a given lot, perform preventive maintenance or the like. Furthermore, typically a set of similar semiconductor tools are managed using a single user interface, which allows for both data viewing (e.g., of assignments of lots to tools) and transaction processing (e.g., manual inputs to enter lots and assign them to tools). Because it likely that the set of tools are at different levels of functioning, when manual inputs are needed, the set of tools are downgraded to a lower (e.g., manual) mode of operation, defeating the benefit of automated operation. Thus it is difficult to integrate automated and manual handling of different lots within a single semiconductor processing line.